001/*
002 * Copyright 2002-2018 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.context.annotation;
018
019import java.lang.annotation.Documented;
020import java.lang.annotation.ElementType;
021import java.lang.annotation.Retention;
022import java.lang.annotation.RetentionPolicy;
023import java.lang.annotation.Target;
024
025/**
026 * Beans on which the current bean depends. Any beans specified are guaranteed to be
027 * created by the container before this bean. Used infrequently in cases where a bean
028 * does not explicitly depend on another through properties or constructor arguments,
029 * but rather depends on the side effects of another bean's initialization.
030 *
031 * <p>A depends-on declaration can specify both an initialization-time dependency and,
032 * in the case of singleton beans only, a corresponding destruction-time dependency.
033 * Dependent beans that define a depends-on relationship with a given bean are destroyed
034 * first, prior to the given bean itself being destroyed. Thus, a depends-on declaration
035 * can also control shutdown order.
036 *
037 * <p>May be used on any class directly or indirectly annotated with
038 * {@link org.springframework.stereotype.Component} or on methods annotated
039 * with {@link Bean}.
040 *
041 * <p>Using {@link DependsOn} at the class level has no effect unless component-scanning
042 * is being used. If a {@link DependsOn}-annotated class is declared via XML,
043 * {@link DependsOn} annotation metadata is ignored, and
044 * {@code <bean depends-on="..."/>} is respected instead.
045 *
046 * @author Juergen Hoeller
047 * @since 3.0
048 */
049@Target({ElementType.TYPE, ElementType.METHOD})
050@Retention(RetentionPolicy.RUNTIME)
051@Documented
052public @interface DependsOn {
053
054        String[] value() default {};
055
056}